There is one broad, general aim of this project. For patients with certain malignant bone tumors, especially osteosarcoma, determine which characteristics of patient, tumor calendar time and treatment are associated with (predictive of) survival from initial treatment to metastasis to death. Osteosarcoma is a rapidly fatal, rare disease of older children and young adults. Any one physician, pathologist, or institution is unlikely to see within reasonable time a sufficient number of cases to provide the fine points of diagnosis, or to evaluate the effectiveness of treatment or the natural history of the disease. Studying osteosarcoma data from many sources is therefore essential in order to accomplish the objective above. In this project ten or more cooperating institutions, all comprehensive cancer centers and all with several years' experience in working with a common cancer data base, will pool their information about certain bone tumors. Already available is a sizable amount of information on such things as cell type, stage site, treatment and follow-up. This will be augmented by further information on the nature of the disease, the treatment and its progression. Most importantly, the difficult problem of uniformity in pathology will be handled by utilizing one pathology laboratory acceptable to all. This is a trial study to determine the feasibility of a cooperative effort to get acceptable data and pathology for a difficult type of cancer. Its cost is low and the results are intended to be useful in the establishment of large, definitive, cooperative studies in the future. There is great interest presently expressed by the musculoskeletal medical community of pathologists, orthopedists and pediatricians in studies such as this one. Every effort will be made to link this project with the work of such other concerned groups, hoping to lead the way to effective cooperation in the near future.